Abstract
1,2-trans-Ribofuranosides are stereoselectively synthesized from 1-O-trimethylsilyl ribofuranose and trimethylsilyl ethers in the presence of a catalytic amount of Me3SiOTf using Ph2Sn=S as an additive, while 1,2-cis-ribofuranosides and 1,2-cis-glucopyranosides are prepared predominantly in the coexistence of LiClO4 in the above reaction.